Mother pleads guilty in death of son, 3; agrees to testify

WEST CHESTER (AP) — A woman charged in the beating death of her young son has pleaded guilty to murder and agreed to testify against her former boyfriend in his upcoming capital murder trial.

Jillian Tait also pleaded guilty Wednesday to conspiracy to commit murder and child endangerment in 3-year-old Scott McMillan's November 2014 death, which prosecutors called a "horror story."

Prosecutors said the plea agreement will spare the 33-year-old Tait a possible death sentence and she will be a "critical witness" in the September murder trial of 25-year-old Gary Lee Fellenbaum III. They said Tait had accepted responsibility and, while her actions may have contributed to Scott's death in Coatesville, Fellenbaum's actions caused it.

"Essentially, your honor, the defendant will act as a living adult witness to what happened in that trailer," First Assistant District Attorney Michael Noone said.

The couple had met working at a Wal-Mart several months earlier and moved in together in a mobile home park along with Fellenbaum's estranged wife, Tait's 6- and 3-year-old children and the Fellenbaums' 11-month-old daughter.

District Attorney Thomas Hogan in 2014 called the case "an American horror story," saying what started as spankings morphed into "concentrated, repeated, escalating abuse" and then over a three-day period the victim "was systematically tortured and beaten to death."

"Scott McMillan had been punched and beaten with blunt and sharp objects, whipped, taped to a chair with electrical tape and beaten, hung up by his feet and beaten and suffered other acts of violence," authorities alleged in court papers.

Prosecutors also alleged the couple went car shopping, bought pizza and engaged in sexual activity as the boy lay dying after weeks of escalating abuse.